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E 551 (AEROSIL 200)

IUPAC name: silicon dioxide
Chemical Formula: SiO2
CAS Number: 60676-86-0
Molecular Weight: 60.08
EC Number: 262-373-8

E 551 (AEROSIL 200), also known as silicon dioxide and silica, is an oxide of silicon with the chemical formula SiO2, most commonly found in nature as quartz and in various living organisms.
In many parts of the world, E 551 (AEROSIL 200) is the major constituent of sand.

E 551 (AEROSIL 200) is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as a synthetic product.
Notable examples include fused quartz, fumed silica, E 551 (AEROSIL 200) gel, opal and aerogels.
E 551 (AEROSIL 200) is used in structural materials, microelectronics (as an electrical insulator), and as components in the food and pharmaceutical industries.

In the majority of silicates, the silicon atom shows tetrahedral coordination, with four oxygen atoms surrounding a central Si atom (see 3-D Unit Cell).
Thus, SiO2 forms 3-dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms.
In contrast, CO2 is a linear molecule.
The starkly different structures of the dioxides of carbon and silicon are a manifestation of the Double bond rule.

E 551 (AEROSIL 200) has several dean crystalline forms, but they almost always have the same local structure around Si and O.
In α-quartz the Si-O bond length is 161 pm, whereas in α-tridymite it is in the range 154–171 pm.
The Si-O-Si angle also varies between a low value of 140° in α-tridymite, up to 180° in β-tridymite. In α-quartz, the Si-O-Si angle is 144°.

Polymorphism
Alpha quartz is the most stable form of solid SiO2 at room temperature.
The high-temperature minerals, cristobalite and tridymite, have both lower densities and indices of refraction than quartz.
The transformation from α-quartz to beta-quartz takes place abruptly at 573 °C.

Since the transformation is accompanied by a significant change in volume, it can easily induce fracturing of ceramics or rocks passing through this temperature limit.
The high-pressure minerals, seifertite, stishovite, and coesite, though, have higher densities and indices of refraction than quartz.

Stishovite has a rutile-like structure where silicon is 6-coordinate.
The density of stishovite is 4.287 g/cm3, which compares to α-quartz, the densest of the low-pressure forms, which has a density of 2.648 g/cm3.

The difference in density can be ascribed to the increase in coordination as the six shortest Si-O bond lengths in stishovite (four Si-O bond lengths of 176 pm and two others of 181 pm) are greater than the Si-O bond length (161 pm) in α-quartz.

The change in the coordination increases the ionicity of the Si-O bond.
More importantly, any deviations from these standard parameters constitute microstructural differences or variations, which represent an approach to an amorphous, vitreous, or glassy solid.

Faujasite silica, another polymorph, is obtained by dealumination of a low-sodium, ultra-stable Y zeolite with combined acid and thermal treatment.
The resulting product contains over 99% silica, and has high crystallinity and specific surface area (over 800 m2/g).
Faujasite-E 551 (AEROSIL 200) has very high thermal and acid stability.
For example, it maintains a high degree of long-range molecular order or crystallinity even after boiling in concentrated hydrochloric acid.

Molten SiO2
Molten E 551 (AEROSIL 200) exhibits several peculiar physical characteristics that are similar to those observed in liquid water: negative temperature expansion, density maximum at temperatures ~5000 °C, and a heat capacity minimum.
Its density decreases from 2.08 g/cm3 at 1950 °C to 2.03 g/cm3 at 2200 °C.

Molecular SiO2
The molecular E 551 (AEROSIL 200) has a linear structure like CO2.
It has been produced by combining silicon monoxide (SiO) with oxygen in an argon matrix.
The dimeric E 551 (AEROSIL 200), (SiO2)2 has been obtained by reacting O2 with matrix isolated dimeric silicon monoxide, (Si2O2).

In dimeric E 551 (AEROSIL 200) there are two oxygen atoms bridging between the silicon atoms with an Si-O-Si angle of 94° and bond length of 164.6 pm and the terminal Si-O bond length is 150.2 pm.
The Si-O bond length is 148.3 pm, which compares with the length of 161 pm in α-quartz.
The bond energy is estimated at 621.7 kJ/mol.

Natural occurrence:

Geology:
SiO2 is most commonly found in nature as quartz, which comprises more than 10% by mass of the Earth's crust.
Quartz is the only polymorph of E 551 (AEROSIL 200) stable at the Earth's surface.
Metastable occurrences of the high-pressure forms coesite and stishovite have been found around impact structures and associated with eclogites formed during ultra-high-pressure metamorphism.
The high-temperature forms of tridymite and cristobalite are known from silica-rich volcanic rocks.
In many parts of the world, E 551 (AEROSIL 200) is the major constituent of sand.

Biology:
Even though it is poorly soluble, E 551 (AEROSIL 200) occurs in many plants such as rice.
Plant materials with high E 551 (AEROSIL 200) phytolith content appear to be of importance to grazing animals, from chewing insects to ungulates.
E 551 (AEROSIL 200) accelerates tooth wear, and high levels of E 551 (AEROSIL 200) in plants frequently eaten by herbivores may have developed as a defense mechanism against predation.

E 551 (AEROSIL 200) is also the primary component of rice husk ash, which is used, for example, in filtration and as supplementary cementitious material (SCM) in cement and concrete manufacturing.[citation needed]

For well over a billion years, silicification in and by cells has been common in the biological world.
In the modern world, it occurs in bacteria, single-celled organisms, plants, and animals (invertebrates and vertebrates).
Prominent examples include:

Tests or frustules (i.e. shells) of diatoms, Radiolaria, and testate amoebae.
E 551 (AEROSIL 200) phytoliths in the cells of many plants, including Equisetaceae, practically all grasses, and a wide range of dicotyledons.
The spicules forming the skeleton of many sponges.
Crystalline minerals formed in the physiological environment often show exceptional physical properties (e.g., strength, hardness, fracture toughness) and tend to form hierarchical structures that exhibit microstructural order over a range of scales. The minerals are crystallized from an environment that is undersaturated concerning silicon, and under conditions of neutral pH and low temperature (0–40 °C).

It is unclear in what ways E 551 (AEROSIL 200) is important in the nutrition of animals.
This field of research is challenging because E 551 (AEROSIL 200) is ubiquitous and in most circumstances dissolves in trace quantities only.
All the same, it certainly does occur in the living body, creating the challenge of creating silica-free controls for purposes of research.

This makes it difficult to be sure when the E 551 (AEROSIL 200) present has had operative beneficial effects, and when its presence is coincidental, or even harmful.
The current consensus is that it certainly seems important in the growth, strength, and management of many connective tissues. This is true not only for hard connective tissues such as bone and teeth but possibly in the biochemistry of the subcellular enzyme-containing structures as well.

Uses:
Structural use
About 95% of the commercial use of E 551 (AEROSIL 200) (sand) occurs in the construction industry, e.g. for the production of concrete

Certain deposits of E 551 (AEROSIL 200) sand, with desirable particle size and shape and desirable clay and other mineral content, were important for sand casting of metallic products.
The high melting point of E 551 (AEROSIL 200) enables it to be used in such applications such as iron casting; modern sand casting sometimes uses other minerals for other reasons.
Crystalline E 551 (AEROSIL 200) is used in hydraulic fracturing of formations which contain tight oil and shale gas.

Precursor to glass and silicon:
E 551 (AEROSIL 200) is the primary ingredient in the production of most glass.
As other minerals are melted with silica, the principle of freezing point depression lowers the melting point of the mixture and increases fluidity.
The glass transition temperature of pure SiO2 is about 1475 K.
When molten E 551 (AEROSIL 200) SiO2 is rapidly cooled, it does not crystallize, but solidifies as a glass. Because of this, most ceramic glazes have E 551 (AEROSIL 200) as the main ingredient.

The structural geometry of silicon and oxygen in glass is similar to that in quartz and most other crystalline forms of silicon and oxygen with silicon surrounded by regular tetrahedra of oxygen centres. The difference between the glass and crystalline forms arises from the connectivity of the tetrahedral units: Although there is no long-range periodicity in the glassy network ordering remains at length scales well beyond the SiO bond length. One example of this ordering is the preference to form rings of 6-tetrahedra.[26]

The majority of optical fibers for telecommunication are also made from silica. It is a primary raw material for many ceramics such as earthenware, stoneware, and porcelain.

E 551 (AEROSIL 200) is used to produce elemental silicon. The process involves carbothermic reduction in an electric arc furnace:

It can also be produced by vaporizing quartz sand in a 3000 °C electric arc. Both processes result in microscopic droplets of amorphous E 551 (AEROSIL 200) fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles, a white powder with extremely low bulk density (0.03-.15 g/cm3) and thus high surface area.[28] The particles act as a thixotropic thickening agent, or as an anti-caking agent, and can be treated to make them hydrophilic or hydrophobic for either water or organic liquid applications

Manufactured fumed E 551 (AEROSIL 200) with maximum surface area of 380 m2/g
E 551 (AEROSIL 200) fume is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy production. It consists of amorphous (non-crystalline) spherical particles with an average particle diameter of 150 nm, without the branching of the pyrogenic product. The main use is as pozzolanic material for high performance concrete. Fumed E 551 (AEROSIL 200) nanoparticles can be successfully used as an anti-aging agent in asphalt binders.

Food, cosmetic, and pharmaceutical applications
Silica, either colloidal, precipitated, or pyrogenic fumed, is a common additive in food production. It is used primarily as a flow or anti-caking agent in powdered foods such as spices and non-dairy coffee creamer, or powders to be formed into pharmaceutical tablets.
It can adsorb water in hygroscopic applications. Colloidal E 551 (AEROSIL 200) is used as a fining agent for wine, beer, and juice, with the E number reference E551.

In cosmetics, E 551 (AEROSIL 200) is useful for its light-diffusing properties[30] and natural absorbency.

Diatomaceous earth, a mined product, has been used in food and cosmetics for centuries. It consists of the E 551 (AEROSIL 200) shells of microscopic diatoms; in a less processed form it was sold as "tooth powder".[citation needed] Manufactured or mined hydrated E 551 (AEROSIL 200) is used as the hard abrasive in toothpaste.

Semiconductors
See also: Surface passivation, Thermal oxidation, Planar process, and MOSFET
E 551 (AEROSIL 200) is widely used in the semiconductor technology

for the primary passivation (directly on the semiconductor surface),
as an original gate dielectric in MOS technology. Today when scaling (dimension of the gate length of the MOS transistor) has progressed below 10 nm E 551 (AEROSIL 200) has been replaced by other dielectric materials like hafnium oxide or similar with higher dielectric constant compared to E 551 (AEROSIL 200),
as a dielectric layer between metal (wiring) layers (sometimes up to 8-10) connecting elements and
as a second passivation layer (for protecting semiconductor elements and the metallization layers) typically today layered with some other dielectrics like silicon nitride.
Because E 551 (AEROSIL 200) is a native oxide of silicon it is more widely used compared to other semiconductors like Gallium arsenide or Indium phosphide.

E 551 (AEROSIL 200) could be grown on a silicon semiconductor surface.
Silicon oxide layers could protect silicon surfaces during diffusion processes, and could be used for diffusion masking.

SiO2 films preserve the electrical characteristics of p–n junctions and prevent these electrical characteristics from deteriorating by the gaseous ambient environment.
Silicon oxide layers could be used to electrically stabilize silicon surfaces.
The surface passivation process is an important method of semiconductor device fabrication that involves coating a silicon wafer with an insulating layer of silicon oxide so that electricity could reliably penetrate to the conducting silicon below.
Growing a layer of E 551 (AEROSIL 200) on top of a silicon wafer enables it to overcome the surface states that otherwise prevent electricity from reaching the semiconducting layer.

Hydrogen Bond Donor Count: 0
Hydrogen Bond Acceptor Count: 2
Rotatable Bond Count: 0
Exact Mass: 59.966755773

Monoisotopic Mass: 59.966755773
Topological Polar Surface Area:
Heavy Atom Count: 3
Isotope Atom Count: 0

Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0

Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 1
Compound Is Canonicalized: Yes

The process of silicon surface passivation by thermal oxidation (E 551 (AEROSIL 200)) is critical to the semiconductor industry.
It is commonly used to manufacture metal-oxide-semiconductor field-effect transistors (MOSFETs) and silicon integrated circuit chips (with the planar process).

E 551 (AEROSIL 200), also known as silica, is an oxide of silicon with the chemical formula SiO2, most commonly found in nature as quartz and in various living organisms.
In many parts of the world, E 551 (AEROSIL 200) is the major constituent of sand.
E 551 (AEROSIL 200) is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as a synthetic product.
Notable examples include fused quartz, fumed silica, E 551 (AEROSIL 200) gel, and aerogels.
E 551 (AEROSIL 200) is used in structural materials, microelectronics (as an electrical insulator), and as components in the food and pharmaceutical industries.

E 551 (AEROSIL 200) is a highly insoluble thermally stable Silicon source suitable for glass, optic and ceramic applications.
Oxide compounds are not conductive to electricity.
However, certain perovskite structured oxides are electronically conductive finding application in the cathode of solid oxide fuel cells and oxygen generation systems.
They are compounds containing at least one oxygen High Purity (99.999%) Silicon Oxide (SiO2)Powderanion and one metallic cation.
They are typically insoluble in aqueous solutions (water) and extremely stable making them useful in ceramic structures as simple as producing clay bowls to advanced electronics and in light weight structural components in aerospace and electrochemical applications such as fuel cells in which they exhibit ionic conductivity.
Metal oxide compounds are basic anhydrides and can therefore react with acids and with strong reducing agents in redox reactions.
Silicon Oxide is also available in pellets, pieces, powder, sputtering targets, tablets, and nanopowder (from American Elements' nanoscale production facilities).
E 551 (AEROSIL 200) is generally immediately available in most volumes.
Ultra high purity, high purity, submicron and nanopowder forms may be considered.
American Elements produces to many standard grades when applicable, including Mil Spec (military grade); ACS, Reagent and Technical Grade; Food, Agricultural and Pharmaceutical Grade; Optical Grade, USP and EP/BP (European Pharmacopoeia/British Pharmacopoeia) and follows applicable ASTM testing standards.
Typical and custom packaging is available.
Additional technical, research and safety (MSDS) information is available as is a Reference Calculator for converting relevant units of measurement.

E 551 (AEROSIL 200) Uses
Structural use
About 95% of the commercial use of E 551 (AEROSIL 200) (sand) occurs in the construction industry, e.g. for the production of concrete (Portland cement concrete).
Certain deposits of E 551 (AEROSIL 200) sand, with desirable particle size and shape and desirable clay and other mineral content, were important for sand casting of metallic products.
The high melting point of E 551 (AEROSIL 200) enables it to be used in such applications such as iron casting; modern sand casting sometimes uses other minerals for other reasons.
Crystalline E 551 (AEROSIL 200) is used in hydraulic fracturing of formations which contain tight oil and shale gas.

The primary use of E 551 (AEROSIL 200) is in the building industry.
E 551 (AEROSIL 200) is used to make ceramics, enamels, concrete, and specialized E 551 (AEROSIL 200) bricks used as refractory materials.
E 551 (AEROSIL 200) is also one of the raw materials from which all kinds of glass are made.
Vitreous E 551 (AEROSIL 200) is an important constituent of specialized types of glass, such as that used in making laboratory equipment, mirrors, windows, prisms, cells, and other kinds of optical devices.
E 551 (AEROSIL 200) is also used as an anti-caking or thickening agent in a variety of foods and pharmaceutical products.
Some other applications of E 551 (AEROSIL 200) include:
In the manufacture of polishing and grinding materials;
As molds for casting;
In the production of elemental silicon;
As a filler in many different kinds of products, including paper, insecticides, rubber products, pharmaceuticals, and cosmetics;
As an additive in paints to produce a low-gloss finish;
In the reinforcement of certain types of plastics.

The primary application of E 551 (AEROSIL 200) gel is as a drying agent.
Packets of E 551 (AEROSIL 200) gel are found in many consumer products, such as electronic equipment, hardware tools, clothing, CD and DVD discs, and foodstuffs.
Because of E 551 (AEROSIL 200)s ability to adsorb moisture from the surrounding air, E 551 (AEROSIL 200) gel prevents rust and other forms of oxidation.
E 551 (AEROSIL 200) gel also has similar applications in industry.
For example, E 551 (AEROSIL 200) is used to dry compressed air, air conditioning systems, and natural gas.
The compound is also used to bleach petroleum oils and as an anti-caking agent for cosmetics and pharmaceuticals.

Why is E 551 (AEROSIL 200) used in food additives?
Manufacturers use E 551 (AEROSIL 200) to make everything from glass to cement, but it also has a use in the food industry as an additive and anticaking agent.
This type of food additive prevents foods from caking or sticking together in clumps.
This may help ensure a product’s shelf life, protect against the effects of moisture, and keep powdered ingredients from sticking together and helping them flow smoothly.

Precursor to glass and silicon
E 551 (AEROSIL 200) is the primary ingredient in the production of most glass.
As other minerals are melted with silica, the principle of Freezing Point Depression lowers the melting point of the mixture and increases fluidity.
The glass transition temperature of pure SiO2 is about 1475 K.
When molten E 551 (AEROSIL 200) SiO2 is rapidly cooled, it does not crystallize, but solidifies as a glass.
Because of this, most ceramic glazes have E 551 (AEROSIL 200) as the main ingredient.
The structural geometry of silicon and oxygen in glass is similar to that in quartz and most other crystalline forms of silicon and oxygen with silicon surrounded by regular tetrahedra of oxygen centers.
The difference between the glass and crystalline forms arises from the connectivity of the tetrahedral units: Although there is no long range periodicity in the glassy network ordering remains at length scales well beyond the SiO bond length.
One example of this ordering is the preference to form rings of 6-tetrahedra.
The majority of optical fibers for telecommunication are also made from silica.
E 551 (AEROSIL 200) is a primary raw material for many ceramics such as earthenware, stoneware, and porcelain.
E 551 (AEROSIL 200) is used to produce elemental silicon.
The process involves carbothermic reduction in an electric arc furnace:
SiO2 + 2 C -> Si + 2 CO

Fumed silica
Fumed silica, also known as pyrogenic silica, is prepared by burning SiCl4 in an oxygen-rich hydrogen flame to produce a "smoke" of SiO2.
SiCl4 + 2 H2 + O2 -> SiO2 + 4 HCl
E 551 (AEROSIL 200) can also be produced by vaporizing quartz sand in a 3000 °C electric arc.
Both processes result in microscopic droplets of amorphous E 551 (AEROSIL 200) fused into branched, chainlike, three-dimensional secondary particles which then agglomerate into tertiary particles, a white powder with extremely low bulk density (0.03-.15 g/cm3) and thus high surface area.
The particles act as a thixotropic thickening agent, or as an anti-caking agent, and can be treated to make them hydrophilic or hydrophobic for either water or organic liquid applications

E 551 (AEROSIL 200) fume is an ultrafine powder collected as a by-product of the silicon and ferrosilicon alloy production.
E 551 (AEROSIL 200) consists of amorphous (non-crystalline) spherical particles with an average particle diameter of 150 nm, without the branching of the pyrogenic product.
The main use is as pozzolanic material for high performance concrete.

Food, cosmetic, and pharmaceutical applications
Silica, either colloidal, precipitated, or pyrogenic fumed, is a common additive in food production.
E 551 (AEROSIL 200) is used primarily as a flow or anti-caking agent in powdered foods such as spices and non-dairy coffee creamer, or powders to be formed into pharmaceutical tablets.
E 551 (AEROSIL 200) can adsorb water in hygroscopic applications.
Colloidal E 551 (AEROSIL 200) is used as a fining agent for wine, beer, and juice, with the E number reference E551.

In cosmetics, E 551 (AEROSIL 200) is useful for its light-diffusing properties and natural absorbency.
Diatomaceous earth, a mined product, has been used in food and cosmetics for centuries.
E 551 (AEROSIL 200) consists of the E 551 (AEROSIL 200) shells of microscopic diatoms; in a less processed form it was sold as "tooth powder".
Manufactured or mined hydrated E 551 (AEROSIL 200) is used as the hard abrasive in toothpaste.

SiO2 Uses (E 551 (AEROSIL 200))
E 551 (AEROSIL 200) is used in the construction industry to produce concrete.
In E 551 (AEROSIL 200)s crystalline form it is used in hydraulic fracturing.
E 551 (AEROSIL 200) is used in the production of glass.
E 551 (AEROSIL 200) is used as a Sedative.
E 551 (AEROSIL 200) is used in the production of produce elemental silicon.
E 551 (AEROSIL 200) is used as anti-caking agent in powdered foods like spices.
E 551 (AEROSIL 200) is used as a fining agent in juice, beer, and wine.
E 551 (AEROSIL 200) is used pharmaceutical tablets.
E 551 (AEROSIL 200) is used in toothpaste to remove tooth plaque.

Semiconductors
See also: Surface passivation, Thermal oxidation, Planar process, and MOSFET
E 551 (AEROSIL 200) is widely used in the semiconductor technology for the primary passivation (directly on the semiconductor surface), as an original gate dielectric in MOS technology.
Today when scaling (dimension of the gate length of the MOS transistor) has progressed below 10 nm E 551 (AEROSIL 200) has been replaced by other dielectric materials like hafnium oxide or similar with higher dielectric constant compared to E 551 (AEROSIL 200), as a dielectric layer between metal (wiring) layers (sometimes up to 8-10) connecting elements to each other and as a secondary passivation layer (for protecting semiconductor elements and the metallization layers) typically today layered with some other dielectrics like silicon nitride.
Because E 551 (AEROSIL 200) is a native oxide of silicon it is more widely used compared to other semiconductors like Gallium arsenide or Indium phosphide.
E 551 (AEROSIL 200) could be grown on a silicon semiconductor surface.
Silicon oxide layers could protect silicon surfaces during diffusion processes, and could be used for diffusion masking.

Surface passivation is the process by which a semiconductor surface is rendered inert, and does not change semiconductor properties as a result of interaction with air or other materials in contact with the surface or edge of the crystal.
The formation of a thermally grown E 551 (AEROSIL 200) layer greatly reduces the concentration of electronic states at the silicon surface.
SiO2 films preserve the electrical characteristics of p–n junctions and prevent these electrical characteristics from deteriorating by the gaseous ambient environment.
Silicon oxide layers could be used to electrically stabilize silicon surfaces.
The surface passivation process is an important method of semiconductor device fabrication that involves coating a silicon wafer with an insulating layer of silicon oxide so that electricity could reliably penetrate to the conducting silicon below.
Growing a layer of E 551 (AEROSIL 200) on top of a silicon wafer enables it to overcome the surface states that otherwise prevent electricity from reaching the semiconducting layer.
The process of silicon surface passivation by thermal oxidation (E 551 (AEROSIL 200)) is critical to the semiconductor industry.
E 551 (AEROSIL 200) is commonly used to manufacture metal-oxide-semiconductor field-effect transistors (MOSFETs) and silicon integrated circuit chips (with the planar process).

Other
Hydrophobic E 551 (AEROSIL 200) is used as a defoamer component.
In E 551 (AEROSIL 200)s capacity as a refractory, E 551 (AEROSIL 200) is useful in fiber form as a high-temperature thermal protection fabric.
E 551 (AEROSIL 200) is used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes.
E 551 (AEROSIL 200) aerogel was used in the Stardust spacecraft to collect extraterrestrial particles.
Pure E 551 (AEROSIL 200) (E 551 (AEROSIL 200)), when cooled as fused quartz into a glass with no true melting point, can be used as a glass fiber for fiberglass.

Water solubility
The solubility of E 551 (AEROSIL 200) in water strongly depends on its crystalline form and is three-four times higher for E 551 (AEROSIL 200) than quartz; as a function of temperature, it peaks around 340 °C.
This property is used to grow single crystals of quartz in a hydrothermal process where natural quartz is dissolved in superheated water in a pressure vessel that is cooler at the top.
Crystals of 0.5–1 kg can be grown over a period of 1–2 months.
These crystals are a source of very pure quartz for use in electronic applications.

What is it?
E 551 (AEROSIL 200) (SiO2), also known as silica, is a natural compound made of two of the earth’s most abundant materials: silicon (Si) and oxygen (O2).
E 551 (AEROSIL 200) is most often recognized in the form of quartz.
E 551 (AEROSIL 200)’s found naturally in water, plants, animals, and the earth.
The earth’s crust is 59 percent silica.
E 551 (AEROSIL 200) makes up more than 95 percent of known rocks on the planet.
When you sit on a beach, E 551 (AEROSIL 200)’s E 551 (AEROSIL 200) in the form of sand that gets between your toes.
E 551 (AEROSIL 200)’s even found naturally in the tissues of the human body.
Though E 551 (AEROSIL 200)’s unclear what role it plays, E 551 (AEROSIL 200)’s thought to be an essential nutrient our bodies need.

Why is E 551 (AEROSIL 200) in food and supplements?
E 551 (AEROSIL 200) is found naturally in many plants, such as:
leafy green vegetables
beets
bell peppers
brown rice
oats
alfalfa

E 551 (AEROSIL 200) is also added to many foods and supplements.
As a food additive, E 551 (AEROSIL 200) serves as an anticaking agent to avoid clumping.
In supplements, E 551 (AEROSIL 200)’s used to prevent the various powdered ingredients from sticking together.

Silica, SiO2, is a white or colorless crystalline compound found mainly as quartz, sand, flint, and many other minerals.
E 551 (AEROSIL 200) is an important ingredient to manufacture a wide variety of materials.
Quartz; Quartz is the most abundant E 551 (AEROSIL 200) mineral.
Pure Quartz is colorless and transparent.
E 551 (AEROSIL 200) occurs in most igneous and practically all metamorphic and sedimentary rocks.
E 551 (AEROSIL 200) is used as a component of numerous industrial materials.
Silicon (Si) has the atomic number 14 and is closely related to carbon.
E 551 (AEROSIL 200) is a relatively inert metalloid.

Silicon is often used for microchips, glass, cement, and pottery.
E 551 (AEROSIL 200) is the most abundant mineral found in the crust of the earth.
One of the most common uses of E 551 (AEROSIL 200) quarts is the manufacturer of glass.
E 551 (AEROSIL 200) is the fourteenth element on the periodic table.
E 551 (AEROSIL 200) can sometimes be found as the substance, quartz which is usually used in jewelry, test tubes, and when placed under pressure, generates an electrical charge.
Quartz is the second most abundant mineral in the Earth's crust.
E 551 (AEROSIL 200) is a clear, glossy mineral with a hardness of 7 on the MOHS scale.
Silica, Sa,is a component of glass and concrete.
A form of E 551 (AEROSIL 200) commonly known as quartz, E 551 (AEROSIL 200) tetrahedra, is the second most common mineral in the earth's crust, it comes in many different forms.

E 551 (AEROSIL 200) is a compound of silicon and oxygen.
Earth's outer crust contains 59% of this material.
E 551 (AEROSIL 200) has three major rock forms, which are quartz, tridymite, and cristobalite.
Silica, commonly known in the form of quartz, is the dioxide form of silicon, SiO2.
E 551 (AEROSIL 200) is usually used to manufacture glass, ceramics and abrasives.
Quartz is the second most common mineral in Earth’s crust.
E 551 (AEROSIL 200)s chemical name is SiO2.

Although quartz is common, E 551 (AEROSIL 200) is usually twinned so industries often Silica; Also known as the E 551 (AEROSIL 200), has a white powdery substance solid.
E 551 (AEROSIL 200) is used in production in many products such as glass, food additive and raw material for production.
The chemical compound silica, also known as E 551 (AEROSIL 200), is known for its hardness since the 16th century.
E 551 (AEROSIL 200) is found in nature in many different forms, such as flint, quartz, and opal.
E 551 (AEROSIL 200) (quartz): Silica, SiO2, is a chemical compound that is composed of one silicon atom and two oxygen atoms.
E 551 (AEROSIL 200) appears naturally in several crystalline forms, one of which is quartz.
E 551 (AEROSIL 200) Quartz- A colorless, ordorless crystal found in different colors such as white, green, black, purple.

E 551 (AEROSIL 200) will not burn to the touch but can cause cancer E 551 (AEROSIL 200), commonly known as E 551 (AEROSIL 200) (and/or quartz), is a prevalent element in the Earth's crust.
One fourth, or twenty-eight percent (to be percise) of the Earth's crust is composed of silica.
Silica:scientific name for a group of minerals composed of silicon and oxygen atoms, (crystalline silica).
Different soils contain all forms of crystalline E 551 (AEROSIL 200) in the form of quartz.
Quartz E 551 (AEROSIL 200) is a colorless/white, black, purple, or green crystals.
E 551 (AEROSIL 200) has no odor and will not burn.
E 551 (AEROSIL 200)'s cancer hazardous.
E 551 (AEROSIL 200) is found in mines and tunnels.
Silica, or E 551 (AEROSIL 200), is the oxide of silicon.
E 551 (AEROSIL 200) is found in nature in several forms; one of which is quartz.
Quartz is the second most common mineral on Earth.

Silica(quartz); Silica(quartz) is a colorless crystal like beryl.
The silica(quartz) come in different colors, such as yellow(citrine), smoky, and purple(amethyst).
The color changes because of transition-metal impurities.
Silica, a white to colorless crystalline compound, is usually in the form of quartz.
E 551 (AEROSIL 200) is used as building stones and to make glass.
E 551 (AEROSIL 200) has covalent bonding and forms a network structure.
Silica, SiO2, has a crystalline form called quartz, which is found in many types of rocks, and is the second most abundant mineral in the Earth’s crust.
This very hard mineral is usually colorless.

E 551 (AEROSIL 200) (quartz): The second most common element in the earth's crust, E 551 (AEROSIL 200) is never found in its natural state, and alloys with a number of different metals.
Silica, SiO2, has a crystalline form called quartz, which is found in numerous types of rocks, and is the second most plentiful mineral in the Earth’s crust.
This very firm mineral is usually colorless E 551 (AEROSIL 200) exists naturally within the earth and our bodies.
There isn’t yet evidence to suggest it’s dangerous to ingest as a food additive, but more research is needed on what role it plays in the body.
Chronic inhalation of E 551 (AEROSIL 200) dust can lead to lung disease.
People who have serious allergies have a vested interest in knowing what additives are in the foods they eat.
But even if you don’t have such allergies, it’s best to be cautious with food additives.
And even minor changes in levels of minerals can have a profound effect on healthy functioning.
A good approach is to eat whole foods and get healthy levels of E 551 (AEROSIL 200).
As with many food additives, consumers often have concerns about E 551 (AEROSIL 200) as an additive.
However, numerous studies suggest there’s no cause for these concerns.

What does the research say?
The fact that E 551 (AEROSIL 200) is found in plants and drinking water suggests it’s safe.
Research has shown that the E 551 (AEROSIL 200) we consume through our diets doesn’t accumulate in our bodies.
Instead, E 551 (AEROSIL 200)’s flushed out by our kidneys.
However, the progressive, often fatal lung disease silicosis can occur from chronic inhalation of E 551 (AEROSIL 200) dust.
This exposure and disease primarily occurs among people who work in:
mining
construction
quarrying
the steel industry
sandblasting

In the majority of silicates, the silicon atom shows tetrahedral coordination, with four oxygen atoms surrounding a central Si atom (see 3-D Unit Cell).
Thus, SiO2 forms 3 dimensional network solids in which each silicon atom is covalently bonded in a tetrahedral manner to 4 oxygen atoms.
In contrast, CO2 is a linear molecule.
The starkly different structures of the dioxides of carbon and silicon is a manifestation of the Double bond rule.
SiO2 has a number of distinct crystalline forms, but they almost always have the same local structure around Si and O.
In α-quartz the Si-O bond length is 161 pm, whereas in α-tridymite it is in the range 154–171 pm.
The Si-O-Si angle also varies between a low value of 140° in α-tridymite, up to 180° in β-tridymite.
In α-quartz, the Si-O-Si angle is 144°.

Polymorphism
Alpha quartz is the stable form of solid SiO2 at room temperature.
The high-temperature minerals, cristobalite and tridymite, have both lower densities and indices of refraction than quartz.
The transformation from α-quartz to beta-quartz takes place abruptly at 573 °C.
Since the transformation is accompanied by a significant change in volume, it can easily induce fracturing of ceramics or rocks passing through this temperature limit.
The high-pressure minerals, seifertite, stishovite, and coesite, though, have higher densities and indices of refraction than quartz.
Stishovite has a rutile-like structure where silicon is 6-coordinate.
The density of stishovite is 4.287 g/cm3, which compares to α-quartz, the densest of the low-pressure forms, which has a density of 2.648 g/cm3.
The difference in density can be ascribed to the increase in coordination as the six shortest Si-O bond lengths in stishovite (four Si-O bond lengths of 176 pm and two others of 181 pm) are greater than the Si-O bond length (161 pm) in α-quartz.
The change in the coordination increases the ionicity of the Si-O bond.
More importantly, any deviations from these standard parameters constitute microstructural differences or variations, which represent an approach to an amorphous, vitreous, or glassy solid.

Faujasite silica, another polymorph, is obtained by dealumination of a low-sodium, ultra-stable Y zeolite with combined acid and thermal treatment.
The resulting product contains over 99% silica, and has high crystallinity and surface area (over 800 m2/g).
Faujasite-E 551 (AEROSIL 200) has very high thermal and acid stability.
For example, it maintains a high degree of long-range molecular order or crystallinity even after boiling in concentrated hydrochloric acid.

Molten SiO2
Molten E 551 (AEROSIL 200) exhibits several peculiar physical characteristics that are similar to those observed in liquid water: negative temperature expansion, density maximum at temperatures ~5000 °C, and a heat capacity minimum.
E 551 (AEROSIL 200)s density decreases from 2.08 g/cm3 at 1950 °C to 2.03 g/cm3 at 2200 °C.

Molecular SiO2
Molecular SiO2 is linear structure.
E 551 (AEROSIL 200) has been produced by combining silicon monoxide with oxygen atoms in an argon matrix.
Dimeric E 551 (AEROSIL 200), (SiO2)2 has been generated by reacting O2 with matrix isolated dimeric silicon monoxide, (Si2O2).
In dimeric E 551 (AEROSIL 200) there are two oxygen atoms bridging between the silicon atoms with an Si-O-Si angle of 94° and bond length of 164.6 pm and the terminal Si-O bond length is 150.2 pm.
The Si-O bond length is 148.3 pm, which compares with the length of 161 pm in α-quartz.
The bond energy is estimated at 621.7 kJ/mol.

Natural occurrence:
Geology
SiO2 is most commonly found in nature as quartz, which comprises more than 10% by mass of the earth's crust.
Quartz is the only polymorph of E 551 (AEROSIL 200) stable at the Earth's surface.
Metastable occurrences of the high-pressure forms coesite and stishovite have been found around impact structures and associated with eclogites formed during ultra-high-pressure metamorphism.
The high-temperature forms of tridymite and cristobalite are known from silica-rich volcanic rocks.
In many parts of the world, E 551 (AEROSIL 200) is the major constituent of sand.

What is E 551 (AEROSIL 200)?
E 551 (AEROSIL 200), or silica, is a combination of silicon and oxygen, two very abundant, naturally occurring materials.
There are many forms of silica.
They all have the same makeup but may have a different name, depending on how the particles arrange themselves.
In general, there are two groups of silica: crystalline E 551 (AEROSIL 200) and amorphous silica.

E 551 (AEROSIL 200) occurs widely in nature.
The Agency for Toxic Substances and Disease Registry (ATSDR) give an idea to just how common this compound is.
E 551 (AEROSIL 200) is easiest to recognize by its common name, quartz, which makes up about 12% of the earth’s crust.
However, E 551 (AEROSIL 200) also occurs naturally in everything from water and plants to animals.
E 551 (AEROSIL 200) sand covers many beaches, and it makes up most of the rocks on earth.
In fact, silica-containing minerals or E 551 (AEROSIL 200) itself make up more than 95% of the earth’s crust.
E 551 (AEROSIL 200) also exists in numerous plants that humans regularly consume, such as:
-dark, leafy greens
-some grains and cereals, such as oats and brown rice
-vegetables, such as beets and bell peppers
-alfalfa
E 551 (AEROSIL 200) also occurs naturally in the human body, though it is still unclear the exact role it plays.

E 551 (AEROSIL 200) is a natural chemical mix of silicon and oxygen that has uses in many food products as an anticaking agent.
E 551 (AEROSIL 200) is generally safe as a food additive, though some agencies are calling for stricter guidelines about the quality and characteristics of the E 551 (AEROSIL 200) found in foods.

Biology
Even though it is poorly soluble, E 551 (AEROSIL 200) occurs in many plants.
Plant materials with high E 551 (AEROSIL 200) phytolith content appear to be of importance to grazing animals, from chewing insects to ungulates.
E 551 (AEROSIL 200) accelerates tooth wear, and high levels of E 551 (AEROSIL 200) in plants frequently eaten by herbivores may have developed as a defense mechanism against predation.
E 551 (AEROSIL 200) is also the primary component of rice husk ash, which is used, for example, in filtration and cement manufacturing.
For well over a billion years, silicification in and by cells has been common in the biological world.
In the modern world it occurs in bacteria, single-celled organisms, plants, and animals (invertebrates and vertebrates).

Prominent examples include:
Tests or frustules (i.e. shells) of diatoms, Radiolaria, and testate amoebae.
E 551 (AEROSIL 200) phytoliths in the cells of many plants, including Equisetaceae, practically all grasses, and a wide range of dicotyledons.
The spicules forming the skeleton of many sponges.
Crystalline minerals formed in the physiological environment often show exceptional physical properties (e.g., strength, hardness, fracture toughness) and tend to form hierarchical structures that exhibit microstructural order over a range of scales.
The minerals are crystallized from an environment that is undersaturated with respect to silicon, and under conditions of neutral pH and low temperature (0–40 °C).

E 551 (AEROSIL 200) is unclear in what ways E 551 (AEROSIL 200) is important in the nutrition of animals.
This field of research is challenging because E 551 (AEROSIL 200) is ubiquitous and in most circumstances dissolves in trace quantities only.
All the same it certainly does occur in the living body, creating the challenge of creating silica-free controls for purposes of research.
This makes it difficult to be sure when the E 551 (AEROSIL 200) present has had operative beneficial effects, and when its presence is coincidental, or even harmful.
The current consensus is that it certainly seems important in the growth, strength, and management of many connective tissues.
This is true not only for hard connective tissues such as bone and tooth but possibly in the biochemistry of the subcellular enzyme-containing structures as well.

SiO2 is an oxide of silicon with a chemical name E 551 (AEROSIL 200).
E 551 (AEROSIL 200) is also called E 551 (AEROSIL 200) or Kalii bromidum or Silicic oxide or silicic acid.
E 551 (AEROSIL 200) is widely found in nature as quartz.
E 551 (AEROSIL 200) is obtained as a transparent to grey, in its crystalline or amorphous powdered form.
E 551 (AEROSIL 200) is odourless and tasteless compound.

While many of the studies Trusted Source on E 551 (AEROSIL 200) have been done on animals, researchers have found no link between the food additive E 551 (AEROSIL 200) and increased risk of cancer, organ damage, or death.
In addition, studiesTrusted Source have found no evidence that E 551 (AEROSIL 200) as an additive in food can affect reproductive health, birth weight, or bodyweight.
The U.S. Food and Drug Administration (FDA) has also recognized E 551 (AEROSIL 200) as a safe food additive.
In 2018, the European Food Safety Authority urged the European Union to impose stricter guidelines on E 551 (AEROSIL 200) until further research could be done.
Their concerns focused on the nano-sized particles (some of which were smaller than 100 nm).
Previously guidelines followed a 1974 paper prepared in association with the World Health Organization.
This paper found the only negative health effects related to E 551 (AEROSIL 200) have been caused by silicon deficiency.
More current research may be changing the guidelines and recommendations.

E 551 (AEROSIL 200) (silica, SiO2, SAS) and titanium dioxide (TiO2) are produced in high volumes and applied in many consumer and food products.
As a consequence, there is a potential human exposure and subsequent systemic uptake of these particles.
In this study we show the characterization and quantification of both total silicon (Si) and titanium (Ti), and particulate SiO2 and TiO2 in postmortem tissue samples from 15 deceased persons.
Included tissues are liver, spleen, kidney and the intestinal tissues jejunum and ileum.
Low-level analysis was enabled by the use of fully validated sample digestion methods combined with (single particle) inductively coupled plasma high resolution mass spectrometry techniques (spICP-HRMS).
The results show a total-Si concentration ranging from <2 to 191 mg Si/kg (median values of 5.8 (liver), 9.5 (spleen), 7.7 (kidney), 6.8 (jejunum), 7.6 (ileum) mg Si/kg) while the particulate SiO2 ranged from <0.2 to 25 mg Si/kg (median values of 0.4 (liver), 1.0 (spleen), 0.4 (kidney), 0.7 (jejunum, 0.6 (ileum) mg Si/kg), explaining about 10% of the total-Si concentration.
Particle sizes ranged from 150 to 850 nm with a mode of 270 nm.
For total-Ti the results show concentrations ranging from <0.01 to 2.0 mg Ti/kg (median values of 0.02 (liver), 0.04 (spleen), 0.05 (kidney), 0.13 (jejunum), 0.26 (ileum) mg Ti/kg) while particulate TiO2 concentrations ranged from 0.01 to 1.8 mg Ti/kg (median values of 0.02 (liver), 0.02 (spleen), 0.03 (kidney), 0.08 (jejunum), 0.25 (ileum) mg Ti/kg).
In general, the particulate TiO2 explained 80% of the total-Ti concentration.
This indicates that most Ti in these organ tissues is particulate material.
The detected particles comprise primary particles, aggregates and agglomerates, and were in the range of 50–500 nm with a mode in the range of 100–160 nm.
About 17% of the detected TiO2 particles had a size <100 nm.
The presence of SiO2 and TiO2 particles in liver tissue was confirmed by scanning electron microscopy with energy dispersive X-ray spectrometry.

E 551 (AEROSIL 200): What Is E 551 (AEROSIL 200)? What’s E 551 (AEROSIL 200) Good For? And Do We Need It?
Ever wondered what that small packet you find in food or supplement bottles is?
You know, the one that says, “Do Not Eat” even though it’s found with your food? Well, that’s called a desiccant.
E 551 (AEROSIL 200)s primary purpose is to absorb excess moisture so fine food particles don’t clump together (the way sugar does).
E 551 (AEROSIL 200)s active ingredient? E 551 (AEROSIL 200), more commonly known as silica, but what is E 551 (AEROSIL 200)?
Let’s delve into this and other questions.

What is E 551 (AEROSIL 200)?
Chemically, E 551 (AEROSIL 200) is a type of quartz, the fusion of the elements silicon (Si) and oxygen (O).
E 551 (AEROSIL 200) is one of the more abundant substances on Earth, making up 59 percent of the crust.
If you’ve been to the beach before, then you will have seen silica.
E 551 (AEROSIL 200)’s just that E 551 (AEROSIL 200) has a different name there: sand
And even though it’s a “rock,” you’ll be surprised to know that E 551 (AEROSIL 200) is also found in organisms, too.
Plants, animals and, yes even us, have trace amounts of it.
Chances are you’ve eaten E 551 (AEROSIL 200) regularly since everything from vegetables to oats have it.

E 551 (AEROSIL 200), also known as silica, is a chemical compound commonly used in food as an anti-caking agent or in cosmetics to prevent corrosion, according to the USDA.
E 551 (AEROSIL 200) helps keep the powders free-flowing and moisture-free and is a common additive in foods like flour, baking powder, sugar and salt, according to the Food and Drug Administration (FDA).
While E 551 (AEROSIL 200) is safe for consumption, it can be unnerving to hear that you may be eating the same additive used in your makeup.
However, this compound is totally safe to use, according to the USDA.
Without E 551 (AEROSIL 200), many of the foods you buy would begin to lump and clot due to moisture absorption.

E 551 (AEROSIL 200) is a chemical compound also known as E 551 (AEROSIL 200) or silox.
The chemical formula for silicon is SiO2.
E 551 (AEROSIL 200) may be found in many forms of nature.
For example, flint, quartz, and opal.
E 551 (AEROSIL 200) is also known as E 551 (AEROSIL 200) SiO2.
E 551 (AEROSIL 200) has three main crystalline varieties: quartz the most abundant, tridymite, and cristobalite.
The mass of the earths crust is 59 percent Silica.
Quartz is mainly made up of silica.

The formula for it is SiO2.
E 551 (AEROSIL 200) has a hardness of 7 on the Mohs scale.
E 551 (AEROSIL 200) has the density of 2.65g/cm3 Silica, SiO2, is composed of Silicone and Oxygen.
E 551 (AEROSIL 200) has been known since ancient times, is found in sand, and is a major component of glass.
E 551 (AEROSIL 200) is a chemical compound, also called E 551 (AEROSIL 200).
E 551 (AEROSIL 200) can sometimes be found as the substance, quartz which is usually used in jewelry, test tubes, and when placed under pressure, generates an electrical charge.
E 551 (AEROSIL 200) is also known as E 551 (AEROSIL 200), the chemical compound is oxide of silicon and the chemical formula is SiO2.
E 551 (AEROSIL 200)’s principle component in most types of glass and substances such as concrete.
E 551 (AEROSIL 200) (quartz); is a naturally occurring minerals that can be found in mines and use in the fabrication of stone and clay products.
E 551 (AEROSIL 200) is odorless and various in color.

E 551 (AEROSIL 200) – comes from silicone after it oxidizes.
E 551 (AEROSIL 200) helps form most hard things like glass, porcelain, and some concrete.
E 551 (AEROSIL 200)s found natural in flint, quarts and opal.
Wesley hamachi Quartz, the clear and opaque mineral, is the second most common mineral in the Earth’s continental crust.
The six-sided shape of the mineral makes it unique and elegant to observe.
Silica: E 551 (AEROSIL 200) can be found in nature as 35 different crystalline forms.
One of its forms is quartz; which can generate current when mechanical stress is applied to it.
Most sand is made up of E 551 (AEROSIL 200) depending on its geographical location.

E 551 (AEROSIL 200) is also used to make glass.
E 551 (AEROSIL 200) (Quartz) is chemical compound E 551 (AEROSIL 200) SiO2.
E 551 (AEROSIL 200) is often found in nature as sand (non coastal), usually in the form of quartz.
The most common form of manufactured E 551 (AEROSIL 200) is glass.
Silica, is a natural compound that has a crystal characteristic and can be found in beach sand.
The most common usage is that of glass in which E 551 (AEROSIL 200) is fused together.

Silica; E 551 (AEROSIL 200) (quartz), the dioxide form of silicon, SiO2, used usually in the form of its prepared white powder chiefly in the manufacture of glass, water glass, ceramics, and abrasives.
E 551 (AEROSIL 200) is the dioxide form of silicon, SiO2, and occurs mostly as quartz sand, flint, and agate.
Silica's powder form is used to manufacture glass, ceramics, etc.
E 551 (AEROSIL 200) SiO2 is the chemical compound E 551 (AEROSIL 200).
E 551 (AEROSIL 200) is formed when silicon is exposed to oxygen.
E 551 (AEROSIL 200) has a covalent bond and is a superior electric insulator, posessing high chemical stability.

E 551 (AEROSIL 200), or silica, is an oxide of silicon with the chemical formula SiO2.
E 551 (AEROSIL 200) is found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite as transparent and tasteless crystals.
Inhalation of fine crystals is toxic to humans leading to respiratory toxicity.
In powdered food products and pharmaceutical tablets, E 551 (AEROSIL 200) is added as a flow agent to absorb water.
Colloidal E 551 (AEROSIL 200) is also used as a wine, beer, and juice fining agent or stabilizer.

E 551 (AEROSIL 200) in Food and Supplements
"Like many other chemical terms that people think are harmful just because they're hard to pronounce, E 551 (AEROSIL 200) sounds ominous," Bonnie Taub-Dix, RD, tells LIVESTRONG.com.
"But E 551 (AEROSIL 200) actually appears naturally in many foods including leafy greens, oats, bell peppers and beets."
When E 551 (AEROSIL 200) comes to supplements, E 551 (AEROSIL 200) is also a common food additive found in many protein powders, according to Julie Upton, RD and co-founder of Appetite for Health.
The compound prevents the whey and other protein powders from clumping over time.
Aside from its use in powdered foods, E 551 (AEROSIL 200) is also used as a stabilizer in the production of beer, according to the FDA.
However, the additive is then filtered out of the alcohol in the final processing steps.

What Does E 551 (AEROSIL 200) Do?
E 551 (AEROSIL 200) is a common substance used in a variety of industrial applications.
Everything from ceramics to glass use E 551 (AEROSIL 200) in one form or another.
In the food industry, E 551 (AEROSIL 200) is most often used as an anti-caking agent.
Many foodstuffs, such as sugar and flour, tend to clump together in moist conditions.
Moisture also promotes bacterial growth and can shorten a product’s shelf life.
E 551 (AEROSIL 200) prevents this by absorbing excess moisture from the atmosphere.
E 551 (AEROSIL 200) can be mixed straight into the food or separated into its own container, as is the case with the desiccant pack.

Is E 551 (AEROSIL 200) Natural or Synthetic?
Since it’s pretty abundant, commercial E 551 (AEROSIL 200) is often derived from natural sources.
Natural quartz is obtained from sand mining and then crushed or milled.
Further processing may be needed to create purer or finer silica, depending on the end-use.

E 551 (AEROSIL 200) is a compound that’s naturally found in the earth’s crust in a crystalline state.
E 551 (AEROSIL 200) can be obtained from mining and purifying quart.
E 551 (AEROSIL 200) is also found in some organisms and animals, the human body (it’s a component of human ligaments, cartilage and musculature), plus some plants (especially grains) and in drinking water.
Additionally, it’s created in labs and used as a common food additive, found in things like baking ingredients, protein powders and dried spices.
This compound has a variety of uses in industries ranging from food and cosmetics to construction and electronics.

What is E 551 (AEROSIL 200) made of?
E 551 (AEROSIL 200)’s composed of a combination of silicon (Si) and oxygen (O), which is why it has the chemical formula SiO2.

What is silica, and how is E 551 (AEROSIL 200) different?
E 551 (AEROSIL 200) goes by the common name silica.
E 551 (AEROSIL 200)’s also sometimes referred to as silicic anhydride or silicate.

Silica/E 551 (AEROSIL 200) comes in several forms, depending on how it’s manufactured, including:
Crystalline silica, which is usually obtained from mining quartz.
Quartz actually comprises a high percentage of the Earth’s crust, so this type is widely available.
This isn’t the form used in foods and can be problematic when inhaled over long periods of time.
Amorphous silica, found in the earth’s sediments and rocks.
This also forms diatomite, diatom E 551 (AEROSIL 200) or diatomaceous earth, which is made from deposits that accumulate over time in the sediment of rivers, streams, lakes and oceans.
This is the type most often used as an anti-caking agent to keep powdered foods free-flowing and to prevent moisture absorption.
Colloidal E 551 (AEROSIL 200), which is used in tablet-making.
This type is found in supplements because it has anti-caking, adsorbent, disintegrant and glidant effects.

Why Is E 551 (AEROSIL 200) Used in Food and Supplements?
Synthetic amorphous E 551 (AEROSIL 200) is the type most often used as a food additive.
E 551 (AEROSIL 200)’s typically manufactured by vapor phase hydrolysis.

Which foods contain E 551 (AEROSIL 200)? You’ll find E 551 (AEROSIL 200) in small amounts added to foods, such as:
flours
protein powders
baking powder
confectioner’s sugar
salt
spice, herb and seasoning mixtures
beer (it is removed from the beer by filtration prior to final processing)
dried egg products
supplement capsules

Silicates are also present in a variety of plant foods included in the human diet, including vegetables and cereal grains, such as leafy greens, peppers, beets, sprouts, rice and oats.
Because it has the ability to block moisture absorption and prevent ingredients from clumping/caking together, E 551 (AEROSIL 200) is used in food products to help retain their texture.
E 551 (AEROSIL 200)’s most often found in granular or powder products, because as the U.S. Food and Drug Administration (FDA) describes it, “it increases speed of dispersion, keeping the food particles separated and permitting the water to wet them individually instead of forming lumps.”

What is E 551 (AEROSIL 200) used for in foods and supplements?
According to the USDA, E 551 (AEROSIL 200) has properties that give it the following functions in foods and supplements:
Works as an anti-caking agent
Prevents corrosion
Defoams
Stops powders from absorbing moisture
Helps to stabilize and clarify beer
Helps carry and distribute flavoring oils
Absorbs alcohol
Helps in processing of wine and gelatin production
Depending on E 551 (AEROSIL 200)’s structure, it can appear as a transparent, tasteless, crystal or an amorphous powder (sometimes called E 551 (AEROSIL 200) powder).

Amorphous E 551 (AEROSIL 200) has a “highly unique physical and chemical properties and potential as an additive in a variety of processing industries,” as described the USDA.
For example, it has a small particle size, high specific surface area, and gelling and thickening abilities.
Something else that makes E 551 (AEROSIL 200) unique is its solubility. E 551 (AEROSIL 200) is not soluble in either water or organic solvents.
In addition to being used in foods supplements and cosmetics, E 551 (AEROSIL 200) is utilized in the production of cans, impermeable films, paints, silicone rubbers, polyester compounds, dental formulations, emulsions, dry pesticides, soil conditioners and turf soil.
The production of E 551 (AEROSIL 200) is one form of “nanotechnology,” which encompasses taking a material and making it into very tiny particles, with dimensions between one and 100 nanometers.
This changes the material’s physical, chemical and biological properties and functions.
While nanotechnology in food processing may help improve the taste, color, look, uniformity and texture of foods, it might also change the material is absorbed and excreted in the human body.

Silicon is the second-most abundant element on Earth, behind oxygen.
Almost 30% of our planet’s crust is made of the stuff, so E 551 (AEROSIL 200) isn’t surprising that it’s also found in food.
However, silicon is rarely found on E 551 (AEROSIL 200)s own.
Instead, E 551 (AEROSIL 200) combines with oxygen and other elements to form silicate materials, which are the largest class of rock-forming materials on Earth and compose 90% of the Earth’s crust.
One such material is silica, or E 551 (AEROSIL 200), which is the most common component of sand.
E 551 (AEROSIL 200) is also found naturally in some foods, and E 551 (AEROSIL 200) is added to many food products and supplements.
E 551 (AEROSIL 200) is commonly used in the form of E 551 (AEROSIL 200) as an anti-caking agent in foods and supplements to keep ingredients from clumping up or sticking together, and it’s sometimes added to liquids and beverages to control foaming and thickness.

Synthetic amorphous E 551 (AEROSIL 200) (SAS, SiO2) and titanium dioxide (TiO2), the latter as a white pigment, are industrially produced in high volumes.
SAS is used as a food additive, is manufactured by several production processes, and consists mainly of nanosized primary particles that form small aggregates and larger agglomerates.
TiO2 as a white pigment is used as a food additive, in personal care products (e.g. toothpaste) and in many other consumer products.
E 551 (AEROSIL 200) contains a fraction of nanosized primary particles (<100 nm).
As a consequence, human exposure and subsequent systemic uptake of these particles becomes likely.
However, only limited data are available on the presence of SiO2 and TiO2 particles in human organs.
We reported only recently on the presence of TiO2 particles in liver and spleen.
In this study, the focus was originally on the determination of SiO2 particles in liver, spleen, kidney and intestinal samples, however, to strengthen the results of the previous study, TiO2 particles were also measured in these new samples.
Since the 1960s, SiO2 as an anti-caking agent and TiO2 as a white pigment are authorized food additives, and in the US as a food color additive (TiO2) and food contact substance in food packaging) and also applied in consumer and medical products.
Sodium, calcium, and magnesium silicates and hydrated silica, SiO2.
nH2O, contain naturally present inorganic Si.
The latter may form small particles in the size range of 1–5 nm and can be found in natural waters, including drinking and mineral waters.
There are limited data on the presence of TiO2 particles in the environment or in untreated food products such as raw milk, vegetables, and meat.

During the life cycle of products, release of SiO2 and TiO2 particles occurs, resulting in direct (oral, lung, and dermal) and indirect (via the environment) human exposure.
Although human tissue levels of the element Ti and particulate TiO2 have been reported, no data are available on human tissue concentrations of the element Si and particulate SiO2.
While no human data on the systemic uptake of SiO2 particles are available, a study with rodents implied limited oral uptake of E 551 (AEROSIL 200) at realistic consumer exposure levels.
Uptake of TiO2 particles by the gut has been studied in animals, but rarely in humans.
The only human volunteer studies conducted with single dose administration suggest that the oral bioavailability of TiO2 is low.
E 551 (AEROSIL 200) should be noted that low oral uptake of nanomaterials can still lead to high organ burdens when there is long-term, frequent exposure in combination with low excretion or high persistence.

In the current study, the presence of SiO2 and TiO2 particles in postmortem liver, spleen, kidney, jejunum, and ileum from 15 deceased persons was determined, enabled by the latest developments in analytical detection methods.
Liver and spleen were included in this study because nanomaterials are generally taken up by the mononuclear phagocyte system (MPS) and thereby typically distribute to the liver and spleen, as well as to the kidney.
Information on the presence of SiO2 and TiO2 particles in intestinal tissues is also considered relevant because of the reported uptake of particles by M-cells in Peyer’s patches, which are mainly found in the jejunum and ileum.
Total-Si and total-Ti concentrations were measured using inductively coupled plasma high-resolution mass spectrometry (ICP-HRMS) while SiO2 and TiO2 particles were measured using single-particle ICP-MS (spICP-MS) on, respectively, a triple quadrupole ICP-MSMS and a ICP-HRMS and instrument.
The tissues were further studied with high resolution scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDX) to confirm the presence and size of SiO2 and TiO2 particles.

Foods With Silica
Compelling data suggests that E 551 (AEROSIL 200) is essential for your health, but more evidence is needed to confirm this.
Typical diets likely contain enough E 551 (AEROSIL 200) that can be absorbed for potential health benefits, despite negative perceptions of silicon as dangerous.

E 551 (AEROSIL 200) occurs as colorless, odorless, tasteless white or colorless crystals or powder.
E 551 (AEROSIL 200)s many different forms can be classified as crystalline, amorphous, or vitreous.
In crystalline forms of E 551 (AEROSIL 200), all of the atoms that make up the substances are arranged in orderly patterns that have the shape of cubes, rhombohedrons, or other geometric figures.
In amorphous E 551 (AEROSIL 200), silicon and oxygen atoms are arranged randomly, without any clear-cut pattern.
Vitreous E 551 (AEROSIL 200) is a glassy form of the compound that may be transparent, translucent, or opaque.
The various forms of E 551 (AEROSIL 200) can be converted from one form to another by heating and changes in pressure.

An especially interesting form of E 551 (AEROSIL 200) is E 551 (AEROSIL 200) gel, a powdery form of amorphous E 551 (AEROSIL 200) that is highly adsorbent.
An adsorbent material (in contrast to an absorbent material) is one that is capable of removing a material, such as water, ammonia, alcohol, or other gases, out of the air.
The second material bonds weakly to the outer surface of E 551 (AEROSIL 200) gel particles.
E 551 (AEROSIL 200) gel is able to adsorb anywhere from 30 to 50 percent of its own weight in water from the surrounding atmosphere before it becomes saturated.
The E 551 (AEROSIL 200) gel is not chemically altered by the process of adsorption and still feels dry even when saturated.
The adsorbed water can be driven off simply by heating the E 551 (AEROSIL 200) gel, allowing the material to regain its adsorbent properties.

HOW E 551 (AEROSIL 200) IS MADE
Although methods are available for synthesizing E 551 (AEROSIL 200), there is no practical reason for doing so.
The abundant quantities of E 551 (AEROSIL 200) found in the earth's crust are sufficient to satisfy all industrial needs.
Among the minerals and earths that contain E 551 (AEROSIL 200) in an uncombined form are quartz, flint, diatomite, stishovite, agate, amethyst, chalcedony, cristobalite, and tridymite.

E 551 (AEROSIL 200) (quartz); "Silica," or E 551 (AEROSIL 200) (SiO2), occurs in either a crystalline or noncrystalline (amorphous) form.
Quartz is a colourless, odourless, non-combustible solid and a component of many mineral dusts.
Silica(quartz);Silica(quartz) is an industrial material, its sand is often used for glass making.
E 551 (AEROSIL 200) is retrieved my mining and a limited environmental impact on earth.
E 551 (AEROSIL 200) (quartz): E 551 (AEROSIL 200) also called E 551 (AEROSIL 200), compound of the two most abundant elements in the Earth's crust.
E 551 (AEROSIL 200) has three main crystalline varieties: quartz (by far the most abundant), tridymite, and cristobalite.
E 551 (AEROSIL 200) (Quartz) : Quartz, the second most common mineral on the earth's crust, belongs to the rhombohedral or trigonal crystal system and can be manufactured using hydrothermal processes in autoclaves.

E 551 (AEROSIL 200), also known as synthetic amorphous E 551 (AEROSIL 200) (SAS), is widely used in food products as a thickener, anticaking agent, and carrier for fragrances and flavors.
Derived from naturally occurring quartz, silicon is the most abundant mineral in the earth’s crust.
E 551 (AEROSIL 200)’s also naturally found in water and plant-based foods, especially cereals like oats, barley and rice.
Silicon should not be confused with silicone, a plastic material that contains silicon and other chemicals used to make breast implants, medical tubing and other medical devices.

Applications:
Silicas exist as white, fluffy powders that are produced through a wet process, yielding E 551 (AEROSIL 200) or E 551 (AEROSIL 200) gel, or a thermal route, yielding pyrogenic (fumed) silica.
In powdered foods, the E 551 (AEROSIL 200) clings to the particles of the foods and prevents them from clumping.
This allows powdery products to remain free-flowing, and other products easy to separate.
E 551 (AEROSIL 200) also functions as a defoaming agent, carrier, conditioning agent, chillproofing agent in malt beverages (like beer) and filter aid.
E 551 (AEROSIL 200)’s also used to manufacture materials such as adhesives and paper for food-packaging materials.
As a direct additive, per U.S. FDA regulation, levels of SAS cannot exceed 2% by weight of the food, and as an indirect additive, it can only be used in the amount required to produce the intended functional effect.

Silica, also called E 551 (AEROSIL 200), compound of the two most abundant elements in Earth’s crust, silicon and oxygen, SiO2.
The mass of Earth’s crust is 59 percent silica, the main constituent of more than 95 percent of the known rocks.
E 551 (AEROSIL 200) has three main crystalline varieties: quartz (by far the most abundant), tridymite, and cristobalite.
Other varieties include coesite, keatite, and lechatelierite.

E 551 (AEROSIL 200) has a molecular weight of 60.08 g/mol.
E 551 (AEROSIL 200) has the lowest coefficient of expansion by heat of any known substance.
E 551 (AEROSIL 200) is not soluble in either water or organic solvents, but it is soluble in hydrofluoric acid.
Heating with concentrated phosphoric acid may slowly dissolve E 551 (AEROSIL 200) as well.
E 551 (AEROSIL 200) exists in the crystalline and amorphous forms.
Their physical states are easily differentiated by X-ray diffraction; the crystalline form exhibits a well-defined diffraction pattern while the amorphous form does not.
The density of crystalline E 551 (AEROSIL 200) (e.g. quartz) and amorphous E 551 (AEROSIL 200) are 2.65 and 2.2 g/cm3 36 , respectively.
E 551 (AEROSIL 200) is transparent, tasteless, crystal or amorphous powder.
The amorphous form of E 551 (AEROSIL 200) may be dissolved by hot concentrated alkaline solutions, but the crystalline form of E 551 (AEROSIL 200) generally is not soluble

E 551 (AEROSIL 200), SiO2, is the low-index, low absorption material used in combination with high-index oxide layer coatings that operate in the UV (~200 nm) to IR (~3 μm) regions.
Typical applications include antireflection coatings for near-UV laser optics, all-dielectric mirrors, beam-dividers, bandpass filters, and polarizers.
E 551 (AEROSIL 200) can be used in combination with specific high-index layers, for example Hafnia, Zirconia, and Tantala, to form multilayer structures with high damage thresholds for specialized UV laser applications.
E 551 (AEROSIL 200) films sometimes are useful in promoting adherence between two dissimilar materials, especially oxide-compositions.
In contrast to the parent quartz form, E 551 (AEROSIL 200) films are amorphous and never obtain the equivalent density, hardness or water impermeability of the crystal form.

Film Properties
Completely oxidized E 551 (AEROSIL 200) films are absorption-free over the range below ~250 nm to at least 5 μm.
Film layers are amorphous and smooth. High mechanical compressive stress limits the thickness the single layer thickness.
When starting from E 551 (AEROSIL 200) pieces, little dissociation and oxygen loss occurs during evaporation, and it is not always necessary to provide a background pressure of oxygen to obtain low-absorbing films.
Adhesion is good to glass, most other oxides, and some polymers.
The films generally grow with an amorphous structure and relatively high packing density so they exhibit minimum index changes when vented to moist air.
The appearance of water absorption bands near 2.9 and 6.2 μm indicates less than perfect packing density.
The refractive index is maximized and water band absorption is minimized with the use of high energy deposition techniques such as IAD or sputter deposition and high substrate temperature.
Low absorption SiO2 films can be produced by oxidizing Silicon Monoxide in a reactive oxygen background.
Evaporation would proceed from a baffled box and therefore the possibility of generating micro-particulates is eliminated.
Alternatively, evaporation can proceed from flat surfaces of large pieces of Silicon Monoxide that are swept by a low-power e-beam.
Films so deposited exhibit low optical absorption, but the possibility exists for particulate emission.

Refractive Index
The refractive indices are dependent on the degree of oxidation, the substrate temperature, and the deposition energy.
The curve below shows typical values.
They can be slightly higher than values for fused Silica.

E 551 (AEROSIL 200), also known as silica, is the most abundant mineral in the Earth's crust, and it is found on every continent in forms ranging from fine powders to giant rock crystals.
In addition to having a natural beauty in its raw mineral form, the substance has useful properties with important applications in everyday life.

Production of E 551 (AEROSIL 200)
Amorphous E 551 (AEROSIL 200) or precipitated E 551 (AEROSIL 200) is obtained by the acidification of sodium silicate solutions. E 551 (AEROSIL 200) gel is washed and dehydrated to produce colourless microporous silica. The reaction involving a trisilicate along with sulphuric acid is given below:
Na2Si3O7 + H2SO4 → 3SiO2 + Na2SO4 + H2O

E 551 (AEROSIL 200) Reactions
E 551 (AEROSIL 200) gets converted to silicon by reducing with carbon.
Fluorine when reacted with E 551 (AEROSIL 200) it produces SiF4 and O2.
E 551 (AEROSIL 200) reacts with hydrofluoric acid to produce hexafluorosilicic acid (H2SiF6).
SiO2 + 6HF → H2SiF6 + 2H2O

Health hazards
E 551 (AEROSIL 200) when ingested orally is non-toxic.
As per a study conducted in the year 2008, found that the higher the levels of E 551 (AEROSIL 200) in water, the risk of dementia decreased.
Therefore, the dose was increased to 10 mg/day of E 551 (AEROSIL 200) in drinking water as the risk of dementia decreased.
When finely divided crystalline E 551 (AEROSIL 200) dust is inhaled, it can lead to bronchitis, lung cancer, or silicosis, due to the lodging of dust in the lungs.
When fine E 551 (AEROSIL 200) particles are inhaled in large enough quantities, it increases the risk of rheumatoid arthritis and lupus.

Frequently Asked Questions
What are the uses of E 551 (AEROSIL 200)?
Approximately 95 per cent of the industrial usage of E 551 (AEROSIL 200) (sand) exists in the building industry, e.g. for concrete production (Portland cement concrete).
Silica, in the form of sand, is used as the key ingredient for the manufacture of metallic components in engineering and other applications of sand casting.
The relatively high melting point of E 551 (AEROSIL 200) allows for its use in these applications.

How is E 551 (AEROSIL 200) produced?
Mostly, E 551 (AEROSIL 200) is obtained via mining activities including sand extraction, and quartz purification.
Quartz is suitable for many purposes, whereas chemical processing is needed to render a more suitable product (e.g. more reactive or fine-grained) purer or otherwise.
E 551 (AEROSIL 200) fume is derived from hot processes such as the processing of ferrosilicon as a by-product.

E 551 (AEROSIL 200) Features
A crystalline solid at normal temperatures, pure E 551 (AEROSIL 200) is white in color and has a density of 2.2 grams per cubic centimeter.
E 551 (AEROSIL 200) is composed of one atom of silicon and two atoms of oxygen; the atoms are bound together tightly making it resistant to many harsh chemicals.
In nature, it takes the form of sand or quartz crystals, and is relatively hard compared to most minerals.
E 551 (AEROSIL 200) is highly resistant to heat, with a melting point of 1,650 degrees Celsius (3,000 degrees Fahrenheit).

E 551 (AEROSIL 200) Types
Although sand and quartz crystals may appear different, they are both made primarily of E 551 (AEROSIL 200).
The chemical makeup of these types is exactly the same, and the properties are generally the same, but they were formed under different conditions.
Sand particles are very small, but tough and hard.
Some quartz crystals have a milky-white appearance.
So-called milky quartz is quite abundant, so it is common to find large rocks of this type of quartz.
Mineral impurities can turn quartz purple, light pink, or other colors, resulting in precious or semi-precious stones such as:
amethyst
citrine
rose quartz
smoky quartz

E 551 (AEROSIL 200) Functions:
E 551 (AEROSIL 200) is used in a number of different ways.
One of the most common uses is to make glass, which is superheated and pressurized E 551 (AEROSIL 200).
E 551 (AEROSIL 200) is also manufactured for use in toothpaste.
Because of its hardness, it helps to scrub away plaque on teeth.
E 551 (AEROSIL 200) is also a major ingredient in cement and used as a pesticide. E 551 (AEROSIL 200) gel is a food additive and desiccant that helps absorb water.

Warning
While E 551 (AEROSIL 200) is for the most part harmless, it poses health risks when inhaled.
In powder form, small particles of the mineral can lodge in the esophagus and the lungs.
E 551 (AEROSIL 200) does not dissolve in the body over time, so it builds up, irritating sensitive tissues.
One such condition is called silicosis, which causes shortness of breath, fever, and coughing and causes the skin to turn blue.
Other conditions include bronchitis and, rarely, cancer.

E 551 (AEROSIL 200) Geography
E 551 (AEROSIL 200) is found just about everywhere in the world, as it is the most common mineral in the crust.
On the surface of the earth, it is prevalent in rocky or mountainous regions.
E 551 (AEROSIL 200) is also present in the form of sand in the deserts and coasts of the world.

The E 551 (AEROSIL 200) (SiO2) Support Films are manufactured using the PELCO® 200nm Silicon Nitride Support Films with the 0.5 x 0.5mm window on a perfectly round 3mm Si frame as a platform.
The E 551 (AEROSIL 200) support films consist of pure and amorphous thermal SiO2 membrane.
The 0.5 x 0.5mm membrane is patterned into 24 ea. apertures with a size varying between 50 x 50µm to 70 x 70µm and etched back to the thermally-deposited amporhous E 551 (AEROSIL 200) leaving a structure-free SiO2 thin membrane of 40nm, 18nm or 8nm, suspended by a 200nm optically transparent Silicon Nitride support mesh.
The bar size between the SiO2 apertures is 25-35µm and the boundary width is 25-55µm.
The design of the mesh and the ratio of mesh suspension and E 551 (AEROSIL 200) Film has been optimized to enable flat E 551 (AEROSIL 200) Support Films with a size of 50 x 50µm to 70 x 70µm.
The result is a E 551 (AEROSIL 200) membrane with a truly superior flatness, ideal for TEM imaging.
E 551 (AEROSIL 200), the compression in the SiO2 film is balanced by the stress in the Silicon Nitride grid structure.
The mesh size of the E 551 (AEROSIL 200) Support Films is comparable to the area size found on most 300 and 400 mesh TEM grids and is considered to be a practical size for many applications.
There are 24 fields of SiO2 support films on each frame.
The boundary of 200nm Silicon Nitride membrane leaves ample area for experiments on Silicon Nitride.

Si/SiO2 wafers from ACS Material are the industry standard for high-quality substrates.
Our high-quality violet wafers are packaged in a 1000 class cleanroom and provide optimal visibility for a variety of nanomaterials, including CVD graphene and graphene flakes.
Silicon/E 551 (AEROSIL 200) substrates are ideal for a variety of uses, including as FET substrates, or in X-ray studies, surface microscopy analysis, or to assist with ellipsometry measurements.
Our Si/SiO2 wafers are polished on the front, etched on the back, and fit in a substrate rack for convenient batch processing and cleaning.
ACS Material provides leading researchers and engineers around the world with the highest-quality nanomaterials and other supplies.
We take pride in our reputation for the purity and consistency of our materials, for the quality of our customer service, and for the fairness of our prices.
Our team is available to answer all your questions to make certain you get the materials you need to take your research to the next level.

Crystalline E 551 (AEROSIL 200) has been associated with pulmonary lung disease.
A number of descriptive terms such as “amorphous silica,” “free silica,” “E 551 (AEROSIL 200) flour,” and “fumed silica” have arisen in the literature as a result of studies related to health and the E 551 (AEROSIL 200) forms.
The definition of these terms has been the result of limitations (both analytical and physical) in qualitative and quantitative analytical methods, as well as definitions associated with the type of manufacturer or process producing the E 551 (AEROSIL 200).
X-ray diffraction and typical mineralogical nomenclature are relevant for the definition of crystalline E 551 (AEROSIL 200) polymorphs, but other E 551 (AEROSIL 200) materials require alternative techniques for analytical definition of those properties which may be health related.

SOLUBILITY:
Solubility depends on crystalline state; generally insoluble in water; soluble in many acids and alkalis

E 551 (AEROSIL 200) General description
E 551 (AEROSIL 200) (SiO2) exists in three crystalline forms, namely quartz, tridymite and cristobalite.
E 551 (AEROSIL 200) reacts with hydrofluoric acid to form silicon tetrafluoride (SiF4) and water. Silicates are formed on reacting SiO2 with alkali melts.
SiO2 is the main component in glass, brick and concrete and also forms the insulator in silicon devices.
The alteration of the surface of SiO2 with (3-aminopropyl)triethoxysilane (APTES) for binding lactate dehydrogenase (LDH) to form an amino layer has been reported.
The silicon-E 551 (AEROSIL 200) structure has been investigated at liquid nitrogen temperature by electron spin resonance spectra.

E 551 (AEROSIL 200), also known as silica, has a chemical formula of SiO2.
E 551 (AEROSIL 200) has a melting point of 1,610°C, a density of 2.648 g/cc, and a vapor pressure of 10-4 Torr at 1,025°C.
E 551 (AEROSIL 200) is commonly found in nature as sand or quartz.
E 551 (AEROSIL 200) is primarily used in the production of glass for windows and beverage bottles.
E 551 (AEROSIL 200) is evaporated under vacuum for the fabrication of optoelectronic and circuit devices.

We recommend heating the substrate to 350°C before attempting to thermally evaporate E 551 (AEROSIL 200).
We anticipate a deposition rate of 2 angstroms per second when the evaporation temperature is at ~1,200°C.
A partial pressure of O2 at 1-2 X 10-4 Torr is recommended.
Under these parameters, we anticipate films to be smooth and amorphous.
The material should be replaced when E 551 (AEROSIL 200) becomes dark or black.
Thermal evaporation of E 551 (AEROSIL 200) is generally not done due to the difficulty associated with this method.
The simplest approach would be to use a relatively inexpensive boat source and change the material as often as possible.
We recommend starting with a thick gauge, Tungsten boat such as our EVS20A015W.
The other option would be to use a tantalum baffle box, like our EVSSO22.
In order for E 551 (AEROSIL 200) to sublime and evaporate, the temperature of the baffle box must be between 1,500°C and 1,800°C.
Once the material's temperature is within this range, there is potential for the material to alloy with the box, causing it to fail.
E 551 (AEROSIL 200) mimics silicon when in the melted state.
Another option would be reactive evaporation.
Silicon monoxide (SiO) can be placed in a tantalum baffle box with a substantial amount of oxygen (we recommend adding 1-2 X 10-4 Torr).
We have not encountered any problems thermally evaporating silicon monoxide.
However, E 551 (AEROSIL 200) is necessary to replace the material after every run.
Silicon monoxide is hard to convert to E 551 (AEROSIL 200) because the bond energy for silicon monoxide is higher than that for E 551 (AEROSIL 200).
As with E 551 (AEROSIL 200), the temperature of the baffle box must be between 1,500°C and 1,800°C in order for evaporation to take place.
Once the material's temperature is within this range, there is potential for the material to alloy with the box, causing it to fail.
Silicon monoxide also mimics silicon when in the melted state.

How E 551 (AEROSIL 200) works
E 551 (AEROSIL 200) causes small abrasions on the body of any pest that comes into contact with the powder.
The pest gradually loses its body fluids, dehydrates and dies.
When bait is added, pests tend to eat the product.
The crystals then abrade their digestive systems and kill them.
E 551 (AEROSIL 200) may take a few days to eliminate pests after the pesticide is applied.

E 551 (AEROSIL 200) Application
The product should be applied to pests or to spots that they frequent.
E 551 (AEROSIL 200) may be sprinkled directly on the leaves of affected plants, avoiding flowers so as not to harm pollinating insects.
E 551 (AEROSIL 200) may also be applied to the soil (without working it in) around the base of plants to be protected.
E 551 (AEROSIL 200) is best to apply E 551 (AEROSIL 200) during dry weather, because E 551 (AEROSIL 200) loses its effectiveness when wet.

Precautions
The product may irritate the respiratory tract if inhaled, so it is best to wear a mask when applying it.
In addition, because it may irritate the eyes, it is best to wear goggles.
E 551 (AEROSIL 200) should be applied on calm days, to keep it from drifting.
Pesticides with E 551 (AEROSIL 200) as the active ingredient are not selective and may harm beneficial garden organisms such as earthworms.
This means that they should be used only as a last resort and for spot treatment only.
Do not use near any body of water or wetland, or dump any pesticide or rinse your equipment there, as this will contaminate the water.
Never dump pesticides down sewers.
Keep out of reach of children.

E 551 (AEROSIL 200) (diatomaceous earth) is made up of approximately 90% silica, the same as is in quartz, sand and agate.
The type of E 551 (AEROSIL 200) found in diatomaceous earth is predominately amorphous E 551 (AEROSIL 200) but will contain small amounts of crystalline E 551 (AEROSIL 200) (which is associated with severe lung toxicity).
Crystalline E 551 (AEROSIL 200) is classified as a known human carcinogen but amorphous E 551 (AEROSIL 200) is not classifiable as to human carcinogenicity.
According to product registration staff at the Washington State Department of Agriculture, all products registered in Washington with E 551 (AEROSIL 200) as the active ingredient contain amorphous silica.
The EPA includes crystalline-free E 551 (AEROSIL 200) in the list of minimal risk inert ingredients and the FDA allows it to be added to food at rates up to 2% by weight.

Two other forms of E 551 (AEROSIL 200) are not true polymorphs. Lechatelierite, an amorphous E 551 (AEROSIL 200), was found at the Barringer Meteor Crater in 1915.
Softer and less dense than quartz, it forms when the heat and pressure of meteoric impacts and lightning fuse quartz sand.
With its noncrystalline structure, lechatelierite is not a mineral, but a mineraloid.
E 551 (AEROSIL 200) occurs in lighting-strike-formed “Libyan desert glass” and in “trinitite,” a glass created when heat from the 1945 nuclear detonation at New Mexico’s Trinity Site altered quartz sand.

In 1984, mogánite, a partially hydrated E 551 (AEROSIL 200) and thus not a true polymorph, was discovered on Spain’s Canary Islands.
Softer and less dense than quartz, E 551 (AEROSIL 200) crystallizes in the monoclinic system.
Mogánite forms from the devitrification of amorphous opaline silica.
In the future, mineralogists expect to identify additional polymorphs and related forms of E 551 (AEROSIL 200) to further demonstrate that, while all quartz is indeed E 551 (AEROSIL 200), all E 551 (AEROSIL 200) is not quartz.

The chemical compound E 551 (AEROSIL 200), also known as E 551 (AEROSIL 200) (from the Latin silex), is an oxide of silicon with the chemical formula SiO2.
E 551 (AEROSIL 200) has been known for E 551 (AEROSIL 200)s hardness since antiquity. E 551 (AEROSIL 200) is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms.
E 551 (AEROSIL 200) is manufactured in several forms including fused quartz, crystal, fumed E 551 (AEROSIL 200) (or pyrogenic silica, trademarked Aerosil or Cab-O-Sil), colloidal silica, E 551 (AEROSIL 200) gel, and aerogel.
E 551 (AEROSIL 200) is used primarily in the production of glass for windows, drinking glasses, beverage bottles, and many other uses.
The majority of optical fibers for telecommunications are also made from silica.
E 551 (AEROSIL 200) is a primary raw material for many whiteware ceramics such as earthenware, stoneware, porcelain, as well as industrial Portland cement.
E 551 (AEROSIL 200) is a common additive in the production of foods, where it is used primarily as a flow agent in powdered foods, or to absorb water in hygroscopic applications.
E 551 (AEROSIL 200) is the primary component of diatomaceous earth which has many uses ranging from filtration to insect control.
E 551 (AEROSIL 200) is also the primary component of rice husk ash which is used, for example, in filtration and cement manufacturing.
Thin films of E 551 (AEROSIL 200) grown on silicon wafers via thermal oxidation methods can be quite beneficial in microelectronics, where they act as electric insulators with high chemical stability.
In electrical applications, E 551 (AEROSIL 200) can protect the silicon, store charge, block current, and even act as a controlled pathway to limit current flow.
A silica-based aerogel was used in the Stardust spacecraft to collect extraterrestrial particles.
E 551 (AEROSIL 200) is also used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes.
As hydrophobic E 551 (AEROSIL 200) E 551 (AEROSIL 200) is used as a defoamer component. In hydrated form, it is used in toothpaste as a hard abrasive to remove tooth plaque.
In E 551 (AEROSIL 200)s capacity as a refractory, E 551 (AEROSIL 200) is useful in fiber form as a high-temperature thermal protection fabric.
In cosmetics, E 551 (AEROSIL 200) is useful for its light-diffusing properties and natural absorbency.
Colloidal E 551 (AEROSIL 200) is used as a wine and juice fining agent. In pharmaceutical products, E 551 (AEROSIL 200) aids powder flow when tablets are formed.
Finally, E 551 (AEROSIL 200) is used as a thermal enhancement compound in ground source heat pump industry.

E 551 (AEROSIL 200) is a common mineral that can be found under different forms (crystalline or amorphous) and is also found in many clays and diatomaceous earth.
The purpose of this trial was to assess, in a factorial 2×2 arrangement, the growth performance of piglets reared with a feeding program including, or not, a crystalline silica-based feed supplement (SI) with or without antibiotics as growth promoters (AGP; chlortetracycline and high levels of Cu and Zn in Phase 1 and chlortetracycline in Phase 2).
All diets were formulated to be iso-caloric and iso-nitrogenous.
An ANOVA was performed on zootechnical parameters with the pen as the experimental unit for all analyses.
Effects of AGP, SI, block (based on sex and body weight), and interaction between AGP and SI were included in the statistical model.
A total of 252 piglets with body weights of 7 kg were reared until 24 kg of body weight and allocated into 36 pens.
According to these results, groups fed with AGP showed improved weight gain, feed intake, and feed conversion during Phase 1, while no significant effect was observed during Phase 2.
Concerning the effect of SI, feed intake was improved by 4.13% during the overall nursery period, compared to groups without SI (729 versus 700 g/day; P < 0,05).
In addition, groups fed SI showed an average daily gain of 3.26% higher than animals without SI during the same period (607 versus 588 g/day; P < 0.05).
This effect leads to an improvement of 2.2% in piglet's weight at the end of the post-weaning phase (24.52 versus 23.99 kg; P < 0.05).
E 551 (AEROSIL 200) was concluded that under our trial conditions, adding crystalline E 551 (AEROSIL 200) to piglet feed (0.02%) increase feed intake, growth rate, and piglet weight at the end of the nursery period.
This mineral additive could offer potential economic benefits to swine producers.

SiO2 has a number of distinct crystalline forms (polymorphs) in addition to amorphous forms.
With the exception of stishovite and fibrous silica, all of the crystalline forms involve tetrahedral SiO4 units linked together by shared vertices in different arrangements.
Silicon-oxygen bond lengths vary between the different crystal forms, for example in α-quartz the bond length is 161 pm, whereas in α-tridymite it is in the range 154–171 pm.
The Si-O-Si angle also varies between a low value of 140° in α-tridymite, up to 180° in β-tridymite. In α-quartz the Si-O-Si angle is 144°.
Fibrous E 551 (AEROSIL 200) has a structure similar to that of SiS2 with chains of edge-sharing SiO4 tetrahedra.

Stishovite, the higher pressure form, in contrast has a rutile like structure where silicon is 6 coordinate.
The density of stishovite is 4.287 g/cm3, which compares to α-quartz, the densest of the low pressure forms, which has a density of 2.648 g/cm3.
The difference in density can be ascribed to the increase in coordination as the six shortest Si-O bond lengths in stishovite (four Si-O bond lengths of 176 pm and two others of 181 pm) are greater than the Si-O bond length (161 pm) in α-quartz.
The change in the coordination increases the ionicity of the Si-O bond.
But more important is the observation that any deviations from these standard parameters constitute microstructural differences or variations which represent an approach to an amorphous, vitreous or glassy solid.
Note that the only stable form under normal conditions is α-quartz and this is the form in which crystalline E 551 (AEROSIL 200) is usually encountered.
In nature impurities in crystalline α-quartz can give rise to colors (see list).

Note also that both high temperature minerals, cristobalite and tridymite, have both a lower density and index of refraction than quartz.
Since the composition is identical, the reason for the discrepancies must be in the increased spacing in the high temperature minerals.
As is common with many substances, the higher the temperature the farther apart the atoms due to the increased vibration energy.
The high pressure minerals, seifertite, stishovite, and coesite, on the other hand, have a higher density and index of refraction when compared to quartz.
This is probably due to the intense compression of the atoms that must occur during their formation, resulting in a more condensed structure.
Faujasite E 551 (AEROSIL 200) is another form of crystalline silica.
It is obtained by dealumination of a low-sodium, ultra-stable Y zeolite with a combined acid and thermal treatment.
The resulting product contains over 99% silica, has high crystallinity and high surface area (over 800 m2/g).

Faujasite-E 551 (AEROSIL 200) has very high thermal and acid stability.
For example, it maintains a high degree of long-range molecular order (or crystallinity) even after boiling in concentrated hydrochloric acid.
Molten E 551 (AEROSIL 200) exhibits several peculiar physical characteristics that are similar to the ones observed in liquid water: negative temperature expansion, density maximum, and a heat capacity minimum.
When molecular silicon monoxide, SiO, is condensed in an argon matrix cooled with helium along with oxygen atoms generated by microwave discharge, molecular SiO2 is produced which has a linear structure.
Dimeric E 551 (AEROSIL 200), (SiO2)2 has been prepared by reacting O2 with matrix isolated dimeric silicon monoxide, (Si2O2).
In dimeric E 551 (AEROSIL 200) there are two oxygen atoms bridging between the silicon atoms with an Si-O-Si angle of 94° and bond length of 164.6 pm and the terminal Si-O bond length is 150.2 pm.
The Si-O bond length is 148.3 pm which compares with the length of 161 pm in α-quartz.
The bond energy is estimated at 621.7 kJ/mol.

In ceramics, SiO2 comes up when technicians talk about glaze chemistry.
E 551 (AEROSIL 200) is an oxide contributed by many ceramic materials: all clays, feldspars and frits.
Quartz or E 551 (AEROSIL 200) powder is almost 100% SiO2.
But the SiO2 in quartz is something completely different than SiO2 in feldspar.
In the latter E 551 (AEROSIL 200) is chemically combined with Al2O3 and KNaO.
Thus when technicians talk about E 551 (AEROSIL 200) they might be speaking of the mineral or the oxide.
Silica, as a mineral, is composed of E 551 (AEROSIL 200) (SiO2).
In bodies SiO2 (as quartz mineral) will almost always exist as unmelted particles embedded in the fired matrix (although finer ones dissolve into the inter-particle glass).
But in glaze chemistry we are talking about silica, the oxide.
All glazes that melt completely and re-solidify contain SiO2, the oxide, many can be 70% or more.
Materials yield their SiO2 to the glaze melt as kiln temperatures increase.
Different materials dissolve into the melt at different temperatures.
The particle size of materials affects the speed at which they dissolve in the melt.
SiO2 is the principle glass former in glazes.
SiO2 can bond with almost any other oxide and bring them into the glass structure.
-SiO2 is the principle, and often only glass forming oxide in glaze.
Normally comprises more than 60% of most glazes and 70% of clays.
Special purpose formulations which lack SiO2 often compromise structural stability and strength.
Floating and container glass are more than 70% SiO2.
-Adjust this in relation to fluxes to regulate melting temperature and gloss.

E 551 (AEROSIL 200) is refractory, E 551 (AEROSIL 200) melts at high temperatures, but E 551 (AEROSIL 200) is readily fluxed to melt lower.
So its percentage regulates the glazes melting range.
-High SiO2 in relation to Al2O3 produces a glossy glaze (and vice versa).
This is called the silica:alumina ratio.
-Increase E 551 (AEROSIL 200) at the expense of B2O3 to make glaze harder, more durable and brilliant.
Boric oxide and E 551 (AEROSIL 200) can be interchanged to adjust glaze melting temperature.
-Decreasing SiO2 increases the melt fluidity; increasing E 551 (AEROSIL 200) raises the melting temperature, increases acid resistance, lowers expansion, increases hardness and gloss, and increases devitrification.
-E 551 (AEROSIL 200) is normal to use as much as possible in any glaze to keep expansion low, to prevent crazing, increase durability and resistance to leaching and enhance body/glaze fired strength.
Note, however, that in certain boracic and feldspathic compositions E 551 (AEROSIL 200) can actually increase crazing so that other low expansion oxides may be needed to reduce glaze expansion.
-With boron and alumina, E 551 (AEROSIL 200) has the lowest expansion of all oxides.
-In clay bodies, quartz mineral particles act as a filler and behave as an aggregate, while chemically combined SiO2 in feldspar, kaolin, ball clay, etc., participates directly in the chemical reactions taking place to build silicate glasses.
Thus the particle size of the parent material is often important in determining whether contributed E 551 (AEROSIL 200) affects the chemistry or participates simply as an aggregate in the fired matrix.

Synonyms:
Silicon dioxide [Wiki]
14639-89-5 [RN]
20243-18-9 [RN]
231-545-4 [EINECS]
231-589-4 [EINECS]
262-373-8 [EINECS]
266-046-0 [EINECS]
272-489-0 [EINECS]
293-303-4 [EINECS]
65997-17-3 [RN]
68611-44-9 [RN]
7631-86-9 [RN]
Chalcedony (SiO2)
Cristobalite [Wiki]
Lussatite
MCM-48
MFCD00011232 [MDL number]
MFCD00132803 [MDL number]
MFCD00147032 [MDL number]
Quartz (SiO2)
SBA-15
SBA-16
Silane, dioxo- [ACD/Index Name]
Silica glass
SILICIC ANHYDRIDE
Stishovite (SiO2)
Tridymite (SiO2)
1343-98-2 [RN]
2-Mercaptoethyl ethyl sulfide silica
483-09-0 [RN]
60 40-63�m silica gel
60 40-63um silica gel
Aerosil
Aerosil 300
Aerosil 380
Aerosil A 300
Aerosil bs-50
Aerosil E 300
Aerosil K 7
Aerosil M-300
Amorphous Silicon Dioxide, Amorphous Silica
Aquafil
AWmissing
C18 Silica Gel, Endcapped, 60A, 40-63um
Cab-O-sil
Cabosil M-5
Cabosil N 5
Cabosil st-1
Cab-O-sperse
Carplex
Carplex 30
Carplex 80
Cataloid
Celite&trade
Celite(R) 560
Celite(R) 577 fine
Celite(R) Filter Cel
Celite(R) Hyflo Supercel
CELITE-545
Chalcedony [Wiki]
CHEMIZORB
Chemizorb Powder
Chemizorb(R) Powder
Christensenite
CHROMOSORB¸ P
COESITE
Colloidal silicon dioxide
Corasil II
Crystalline Silica Quartz
Crystoballite
Crysvarl
Dicalite
Dioxide, Silicon
EXtrelut NT
EXtrelut NT Refill pack
EXtrelut(R) NT
EXtrelut(R) NT Refill pack
Extrusil
Fibrous Glass
FINE GRAIN SAND
Geduran Si 60
Geduran(R) Si 60
Hyflo(R) Super Cel(R)
KEATITE
LiChroprep Si 60 (15-25 µm)
LiChroprep Si 60 (25-40 µm)
LiChroprep Si 60 (40-63 µm)
LiChroprep(R) Si 60 (15-25 µm)
LiChroprep(R) Si 60 (25-40 µm)
LiChroprep(R) Si 60 (40-63 µm)
LiChrosorb(R) Si 100 (10 µm)
LiChrospher(R) Si 60 (5 µm)
Ludox
Manosil vn 3
Metacristobalite
Micro particles based on silicon dioxide
Min-U-sil
Monodisperse silicon dioxide
Nalcoag
Neosil
Neosyl
Non-porous silica
Non-porous silicon dioxide
Novaculite [Wiki]
Nyacol
Onyx
Opal
Parteck(R) SLC 500
PharmPrep P Si 100, 20µm
PharmPrep P Si100, 10µm
PharmPrep(R) P Si 100, 20µm
PharmPrep(R) P Si100, 10µm
Pigment White 27
Porasil
Positive sol 232
Quso G 30
Quso G32
Quso G-32
Sand 50-70 mesh
Sand, washed
Santocel
sea sand
Sicron F 300
Siderite (SiO2)
Sikron F 100
silanedione
Silanox 101
Silica nanoparticles
Silica, fumed, hydrophobic
Silica, hydrate(8CI,9CI)
Silicagel 60A 20-45 micron
Silicagel 60A 6-35 micron
Silicamissing
Siliceous earth
SILICON(IV)OXIDE
silicondioxide
Silikil
Silikill
Siliziumdioxid
Sillikolloid
Siloxid
Silver bond B
Sipernat
Snowit
Snowtex 30
Snowtex O
STISHOVITE
Superfloss
Syton 2X
SYTON HT-50
Tiger-eye
TLC Silica gel 60 H
TLC-Silica gel 60 GF₂₅S24;
Tokusil TPLM
Vitasil 220
Vulkasil
Vulkasil S
Wessalon
Zeofree 80
ZEOprep 60
Zipax
Zorbax sil
α-Cristobalite
α-Crystobalite
α-Quartz
Silica
Quartz
Dioxosilane
7631-86-9
Diatomaceous earth
Cristobalite
Tridymite
Infusorial earth
Silicic anhydride
KIESELGUHR
14808-60-7
Aerosil
Sand
112945-52-5
Crystalline silica
Diatomaceous silica
Dicalite
Wessalon
Glass
Ludox
Nyacol
112926-00-8
61790-53-2
Zorbax sil
Silica, amorphous
Cab-O-sil
ChristenseniteCrystoballite
Silicon(IV) oxide
Siliceous earth
Synthetic amorphous silica
Amorphous silica
60676-86-0
Silica, colloidal
QUARTZ (SIO2)
14464-46-1
Chalcedony
Diatomite
Agate
Silica vitreous
Cab-o-sil M-5
colloidal silica
Fused silica
Quartz glass
Quartz sand
Silica slurry
Min-U-Sil
15468-32-3
91053-39-3
Silicon dioxide, fumed
Siliziumdioxid
SILICA, VITREOUS
UNII-ETJ7Z6XBU4
Kieselsaeureanhydrid
68855-54-9
CHEBI:30563
SiO2
(SiO2)n
43-63C
ETJ7Z6XBU4
13778-37-5
13778-38-6
17679-64-0
Celite
Sand, Ottawa
Sand, Sea
silica gel desiccant
Calcined diatomite
MFCD00011232
MFCD00217788
Sillikolloid
Acticel
Aerosil 380
Amethyst
Aquafil
Carplex
Cataloid
Crysvarl
Extrusil
Flintshot
Nalcoag
Novaculite
Porasil
Santocel
Silikil
Silikill
Siloxid
Sipernat
Superfloss
Vulkasil
Cherts
Neosil
Neosyl
Snowit
Aerosil-degussa
Imsil
Metacristobalite
Zipax
Quartz silica
alpha-Quartz
Fossil flour
Fumed silica
Quartz dust
Rock crystal
Rose quartz
Silica dust
Silica glass
White carbon
Chromosorb P
Silica particles
Tiger-eye
Vulkasil S
Celite superfloss
Cristobalite dust
Snowtex O
Corasil II
Silver bond B
Cab-O-sperse
alpha-Cristobalite
alpha-Crystobalite
Tokusil TPLM
Dri-Die
Gold bond R
Cabosil st-1
Manosil vn 3
Sil-Co-Sil
Ultrasil VH 3
Ultrasil VN 3
Aerosil bs-50
Aerosil K 7
Cabosil N 5
Carplex 30
Carplex 80
Pigment White 27
Siderite (SiO2)
Snowtex 30
Syton 2X
Tridymite 118
Zeofree 80
Cab-O-grip II
Silicon(IV) oxide, amorphous
Tridimite [French]
Amorphous silica gel
HI-Sil
Glass wool, for laboratory use
Positive sol 232
Aerogel 200
Aerosil 300
Amorphous silica dust
Ludox hs 40
Silanox 101
Silica (SiO2)
Vitasil 220
Aerosil A 300
Aerosil E 300
Aerosil M-300
Cristobalite (SiO2)
Nyacol 830
Sibelite M 3000
Sibelite M 4000
Sibelite M 6000
Quso 51
Sicron F 300
Sikron F 100
Spectrosil
Accusand
Coesite
Fuselex
Nalcast
Nyacol 1430
Optocil
Quartzine
Quarzsand
Rancosil
Suprasil
Tridimite
Siltex
Vitreous quartz
Vitreous silica
Tridymite dust
W 12 (Filler)
beta-Quartz
Fused quartz
MIN-U-sil alpha quartz
Quartz-beta
Quso G 30
Amorphous quartz
Nalco 1050
Quazo puro
Vitrified silica
MFCD00163736
Pyrogenic colloidal silica
Silane, dioxo-
Crystallized silicon dioxide
Optocil (quartz)
CP-SilicaPLOT
Diatomaceous earth, calcined
Admafine SO 25H
Admafine SO 25R
Admafine SO 32H
Admafine SO-C 2
Admafine SO-C 3
Cristobalite asbestos
Keatite (SiO2)
Sg-67
Tridymite (SiO2)
Stishovite (SiO2)
ED-C (silica)
Fuselex ZA 30
As 1 (silica)
CCRIS 2475
CCRIS 3699
DQ12
Agate (SiO2)
Celite 545
Dimethyl siloxanes and silicones
Fumed synthetic amorphous silica
Silica, crystalline - tridymite
FB 5 (silica)
Fuselex RD 120
Corning 7940
Denka F 90
Denka FB 30
Denka FB 44
Denka FB 74
Denka FS 30
Dri-Die 67
D & D
SF 35
Elsil BF 100
Fuselex RD 40-60
EINECS 231-545-4
EINECS 238-455-4
EINECS 238-878-4
EINECS 239-487-1
HK 400
TGL 16319
CI 7811
Silica, crystalline, quartz
Silica, crystalline: quartz
GP 7I
CAB-O-SIL N-70TS
Silica, crystalline tridymite
Kieselgel
Seesand
Silica, crystalline - quartz
AF-SO 25R
Siilca
Zorbax
quartz-glass
Silicom dioxide
Silica flour (powdered crystalline silica)
Silica, crystalline: tridymite
silica-gel
Fused-silica
Silica,fumed
AI3-25549
GP 11I
RD 8
silica-
QuarZ
Silica, fumed
U 333
W 006
Silicon di-oxide
Tridymite [Silica, crystalline]
CRS 1102RD8
Silica Dispersion
SiO2 Nanopowder
Silica gel G
Silica, crystalline: cristobalite
Silica, tridymite
SiO2 Nanospheres
EF 10
FS 74
MR 84
EINECS 262-373-8
Silica gel, ASTM
Silica Nanoparticles
Methyl3-oxohexanoate
Siliceous sand, CP
BF 100
EQ 912
QG 100
RD 120
Aerosil 200
Celite 503